Thackary Binx, the immortal black cat, in the film "Hocus Pocus."

Black cats, beware. Long associated with witches, bad luck and the dark side, black felines are often used for pranks, party props and even satanic, sacrificial rituals around Halloween.

"This is a time when blood rituals take place," said Hedy Litke, director of animal placement at the ASPCA. "Black cats are often sacrificed."

Such is their popularity that many shelters in New York and around the country ban adoptions of black cats in the weeks and days preceding Oct. 31 to protect them from potentially grisly endings. "Black cats are in demand at this time of year," said Sandra DeFeo of the Humane Society, which prohibits adoptions of black cats during most of October and the beginning of November. "We want to be protective of the animals."

Two years ago, shelter workers at the Brooklyn Animal Resource Coalition in Williamsburg were on red alert when a woman dressed as a witch came in and insisted on adopting a black cat. "We told her no," said BARC Vice President Vinny Spinola, whose shelter receives more than a dozen requests for black cats each Halloween and also has issued a moratorium on black-cat adoptions. "We knew she only wanted the cat for a Halloween ritual."

Litke at ASPCA recalled a spooky episode with a woman who had adopted a black cat. "We called two days later to check on the cat, and she told us the cat was dead."

The woman wouldn't tell the ASPCA how the cat died but said workers could pick up the body. "When we got there, she was gone ... and so was the cat," Litke said. "All we found was an empty apartment. We never found the body."

Sacrificing cats began in medieval times, when the Church decreed that felines were friends of the devil. With their darting eyes and sinister-looking coats the color of death, black cats became known as witches' mascots. They also were known as "familiars," through which witches could communicate with the spiritual world. Cats weren't always regarded with suspicion. The Egyptians regarded cats as sacred, mummifying them and burying them alongside their royal owners. Shelters like BARC don't go that far but also hold cats black or otherwise in high regard. "What is the point of doing what we do if we're going to take black cats off the streets and put them into a life of hell, where they are burned, mutilated or used for sacrifice?" Spinola said.